The PRTL file is a Title Template file, and can be used ONLY in PrE, or PrPro. An SRT file is a sub-title file - something entirely different. Now, though not directly using the PRTL file, one can use any number of Sub-title creation programs to create an SRT file, like Subtitle Workshop: http://www.softpedia.com/get/Multimedia/Video/Other-VIDEO-Tools/Subtitle-Workshop.shtml.
The only workflow, that I can think of, would be to open the PRTL file in PrE's Titler, then Select the Text, Copy that, then Paste it into NotePad, for use in the Sub-title creation program. Note: any Styles, or formatting will not Copy/Paste, so they would have to added in the Sub-title production program.
Exactly how will you need to use that .SRT file? There might be another way to go about getting what you need.
I want to convert the subtitles from Premier CS6 to any other format I can edit it. I need those subtitles in STL file.
I have never found any other program, besides Premiere (Pro, or Elements), that can Open PRTL files. Even Photoshop and Illustrator cannot (or could not - do not have Ps, or AI CC, so cannot test that). I used to file Feature Requests for Ps to support PRTL's, but finally gave up on that. Also, it seems that PRTL might be a dead end, in the future, as Adobe is even scaling back in PrPro.
The Copy/Paste option is the only way that I have ever been able to work with JUST the text, in other programs.
Good luck, and if you DO find some non-Premiere program, that CAN Open the PRTL's, please post of that.
I need a STL file from subtitles created on Premier CS6. That's it.
I see that your thread has been in the Premiere Pro as well as the Premiere Elements Forum.
Specific to what I believe that you asked, I is no to convert a PRTL file into a STL file with Premiere Elements or Premiere Pro that are using the PRTL format for their title files. As for other programs for the PRTL to STL conversion, I know of none.
A Google search for "PRTL converter" did bring up one software named PRTL converter, claiming to convert the PRTL from one format to another. I have not explored this to define "PRTL" as well as "one format to another" in terms of what that was all about.